forwarding.tex

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\end{description}

Note that it is possible to configure and run both kernel-level and
user-level Click. In that case, typically
{\stt kernel-click-config-generator-file} and
{\stt user-click-config-generator-file} would point to different
generators. Otherwise, a single common generator wouldn't know whether
to generate configuration for kernel-level Click or for user-level
Click.

\end{description}

\item{\tt plumbing}: this delimits a part of the router configuration
  used for the plumbing together of packet forwarding functionality.
  Multicast forwarding configuration must be part of this grouping.
\item{\tt mfea4}: this delimits the part of the router configuration
  related to multicast forwarding of IPv4 packets.

  The following multicast forwarding parameters can be configured:
\begin{description}
\item{\tt disable}: this takes the value {\stt true} or {\stt false},
  and disables or enables all IPv4 multicast forwarding on the
  router~\footnote{Note that prior to XORP Release-1.1, the {\tt enable}
  flag was used instead of {\tt disable}.}.
  The default is {\stt false}.
\item{\tt interface}: this specifies an interface to be used for
  multicast IPv4 forwarding.  Each interface to be used for multicast
  forwarding needs to be explicitly listed.

  In addition to the normal network interfaces, a special-purpose
  interface called {\stt register\_vif} needs to be configured for
  PIM-SM (see Chapter \ref{pimsm}) to be able to send
  register-encapsulated packets to the PIM Rendezvous Point.  PIM-SM
  will not work correctly unless this is configured.  The {\stt
  register\_vif} interface must be configured with a vif also called
  {\stt register\_vif}.
\item{\tt vif}: this specifies a vif to be used for multicast IPv4
  forwarding.  Each vif to be used for multicast forwarding needs to
  be explicitly listed.

  Each vif can take the following parameter:
\begin{description}
\item{\tt disable}: this takes the value {\stt true} or {\stt false},
  and disables or enables multicast forwarding on this vif~\footnote{Note
  that prior to XORP Release-1.1, the {\tt enable} flag was used instead of
  {\tt disable}.}.
  The default is {\stt false}.
\end{description}
\end{description}
\item{\tt traceoptions}: this directive delimits the configuration of
  debugging and tracing options for multicast forwarding.
\begin{description}
\item{\tt flag}: this directive is used to specify which tracing
  options are enabled.  Possible parameters are:
\begin{description}
\item{\tt all}: this directive specifies that all tracing
  options should be enabled.  Possible parameters are:
\begin{description}
\item{\tt disable}: this takes the value {\stt true} or {\stt false},
  and disables or enables tracing~\footnote{Note
  that prior to XORP Release-1.1, the {\tt enable} flag was used instead of
  {\tt disable}.}. The default is {\stt false}.
\end{description}
\end{description}
\end{description}
\item{\tt mfea6}: this delimits the part of the router configuration
  related to multicast forwarding of IPv6 packets.  The possible
  parameters are the same as for {\stt mfea4}, but affect IPv6
  multicast forwarding rather than IPv4.
\end{description}

\newpage

\subsection{Example Configurations}
\vspace{0.1in}
\noindent\framebox[\textwidth][l]{\scriptsize
\begin{minipage}{6in}
\begin{alltt}
\begin{tabbing}
xx\=xx\=xx\=xx\=xx\=\kill
fea \{\\
\>unicast-forwarding4 \{\\
\>\>disable: false\\
\>\}\\
\>unicast-forwarding6 \{\\
\>\>disable: true\\
\>\}\\
\}\\
plumbing \{\\
\>mfea4 \{\\
\>\>disable: false\\
\>\>interface dc0 \{\\
\>\>\>vif dc0 \{\\
\>\>\>\>disable: false\\
\>\>\>\}\\
\>\>\}\\
\>\>interface register\_vif \{\\
\>\>\>vif register\_vif \{\\
\>\>\>\>/* Note: this vif should be always enabled */\\
\>\>\>\>disable: false\\
\>\>\>\}\\
\>\>\}\\
\>\>traceoptions \{\\
\>\>\>flag all \{\\
\>\>\>\>disable: false\\
\>\>\>\}\\
\>\>\}\\
\>\}\\
\\
\>mfea6 \{\\
\>\>disable: false\\
\>\>interface dc0 \{\\
\>\>\>vif dc0 \{\\
\>\>\>\>disable: false\\
\>\>\>\}\\
\>\>\}\\
\>\>interface register\_vif \{\\
\>\>\>vif register\_vif \{\\
\>\>\>\>/* Note: this vif should be always enabled */\\
\>\>\>\>disable: false\\
\>\>\>\}\\
\>\>\}\\
\>\}\\
\}
\end{tabbing}
\end{alltt}
\end{minipage}
}

\vspace{0.1in}
The configuration above enables unicast IPv4 forwarding, but disables
IPv6 unicast forwarding.

In addition, it enables multicast forwarding for IPv4 and IPv6 on
interface/vif {\stt dc0/dc0}, and enables the register vif for use by
PIM-SM multicast routing.

\newpage
\vspace{0.1in}
\noindent\framebox[\textwidth][l]{\scriptsize
\begin{minipage}{6in}
\begin{alltt}
\begin{tabbing}
xx\=xx\=xx\=xx\=xx\=xx\=xx\=\kill
interfaces \{\\
\>interface eth0 \{\\
\>\>description: "control interface"\\
\>\>vif eth0 \{\\
\>\>\>address 10.10.10.10 \{\\
\>\>\>\>prefix-length: 24\\
\>\>\>\>broadcast: 10.10.10.255\\
\>\>\>\}\\
\>\>\}\\
\>\>mac: aa:bb:cc:dd:ee:ff\\
\>\>mtu: 1500\\
\>\}\\
\}\\
\\
fea \{\\
\>unicast-forwarding4 \{\\
\>\>disable: false\\
\>\}\\
\\
\>click \{\\
\>\>disable: false\\
\>\>duplicate-routes-to-kernel: false\\
\\
\>\>kernel-click \{\\
\>\>\>disable: true\\
\>\>\>install-on-startup: true\\
\>\>\>kernel-click-modules: "/path/to/proclikefs.o:/path/to/click.o";\\
\>\>\>mount-directory: "/click"\\
\>\>\>kernel-click-config-generator-file: "/path/to/kernel\_click\_config\_generator"\\
\>\>\}\\
\\
\>\>user-click \{\\
\>\>\>disable: false\\
\>\>\>command-file: "/path/to/click"\\
\>\>\>command-extra-arguments: "-R"\\
\>\>\>command-execute-on-startup: true\\
\>\>\>control-address: 127.0.0.1\\
\>\>\>control-socket-port: 13000\\
\>\>\>startup-config-file: "/dev/null"\\
\>\>\>user-click-config-generator-file: "/path/to\_user\_click\_config\_generator"\\
\>\>\}\\
\>\}\\
\}\\
\end{tabbing}
\end{alltt}
\end{minipage}
}

\vspace{0.1in}
The configuration above enables configures both kernel-level and
user-level Click (eventually on Linux given that it contains two kernel
Click modules), but enables only user-level Click.


\section{Monitoring the Forwarding Engine}

The {\stt show mfea dataflow} command can be used to display
information about MFEA IPv4 dataflow filters:

\vspace{0.1in}
\noindent\framebox[\textwidth][l]{\scriptsize
\begin{minipage}{6in}
\begin{alltt}
\begin{tabbing}
xx\=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx\=xxxxx\=xx\=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx\=xx\=\kill
user@hostname> \textbf{show mfea dataflow}\\
Group                              \>\>\>\>Source\\
224.0.1.20                         \>\>\>\>10.2.0.1\\
\>Measured(Start|Packets|Bytes)\>Type\>Thresh(Interval|Packets|Bytes)\>\>Remain\\
\>1091667269.982158|0|?        \><= \>\>210.0|0|?                \>\>202.434319\\
\>1091667269.984406|?|0        \>>= \>\>100.0|?|102400           \>\>92.436567
\end{tabbing}
\end{alltt}
\end{minipage}
}
\vspace{0.1in}

Note that the above information is shown only if the filters are kept at
user-space. If the filters are kept at kernel-space (\eg in case of UNIX
system with advanced multicast API support), then currently \xorpsh
cannot be used to show the information. In that case, the appropriate system
command should be used instead (e.g., the UNIX {\stt netstat -gn} command).

The {\stt show mfea interface} command can be used to display
information about MFEA IPv4 interfaces:

\vspace{0.1in}
\noindent\framebox[\textwidth][l]{\scriptsize
\begin{minipage}{6in}
\begin{alltt}
\begin{tabbing}
xxxxxxxxxxxxx\=xxxxxxxxx\=xxxxxxxxxxxxx\=xxxxxxxxxxxxxxxx\=xxxxx\=\kill
user@hostname> \textbf{show mfea interface}\\
Interface \>State  \>Vif/PifIndex \>Addr       \>Flags\\
dc0       \>UP     \>0/6          \>10.4.0.1   \>MULTICAST BROADCAST KERN\_UP\\
dc2       \>UP     \>1/8          \>10.3.0.2   \>MULTICAST BROADCAST KERN\_UP\\
register\_vif \>UP \>2/6          \>10.4.0.1   \>PIM\_REGISTER KERN\_UP
\end{tabbing}
\end{alltt}
\end{minipage}
}
\vspace{0.1in}

The {\stt show mfea interface address} command can be used to display
information about MFEA IPv4 interface addresses:

\vspace{0.1in}
\noindent\framebox[\textwidth][l]{\scriptsize
\begin{minipage}{6in}
\begin{alltt}
\begin{tabbing}
xxxxxxxxxxxxx\=xxxxxxxxxxxxxxxx\=xxxxxxxxxxxxxxxxxxx\=xxxxxxxxxxxxxxxx\=xxxxxxx\kill
user@hostname> \textbf{show mfea interface address}\\
Interface  \>Addr          \>Subnet           \>Broadcast     \>P2Paddr\\
dc0        \>10.4.0.1      \>10.4.0.0/24      \>10.4.0.255    \>0.0.0.0\\
dc2        \>10.3.0.2      \>10.3.0.0/24      \>10.3.0.255    \>0.0.0.0\\
register\_vif \>10.4.0.1   \>10.4.0.1/32      \>10.4.0.1      \>0.0.0.0
\end{tabbing}
\end{alltt}
\end{minipage}
}

The equivalent commands for IPv6 multicast forwarding are:
\begin{description}
\item{\stt show mfea6 dataflow}
\item{\stt show mfea6 interface}
\item{\stt show mfea6 interface address}
\end{description}
\vspace{0.1in}